Factors adversely affecting prognosis after hepatectomy for hepatic metastases include residual tumor, hepatic lymph node metastases, satellite metastases, extrahepatic metastases, four or more hepatic metastases, resection margins of less than 10 mm, and carcinoembryonic antigen and carbohydrate antigen 19-9 values higher than normal preoperatively and 1 month postoperatively. As no significant differences were observed in terms of the H-number stipulated by the Japanese Classification of Colorectal Carcinoma, a new staging system based on the number of lymph node metastases from the primary lesion, the number of liver metastases number, and the size of metastatic tumors was developed. The proposed staging system appears to be useful in predicting the prognosis of patients with metastatic liver tumors from colorectal cancer. Favorable patient selection criteria for liver resection are: 1) medical fitness for hepatectomy; 2) radical resection of the primary colorectal lesion; 3) metastatic tumors anatomically confined within the liver allowing adequate preservation of the liver parenchyma; 4) no signs of disseminated disease; 5) no signs of hepatic lymph node metastases; 6) four or fewer metastatic tumors; and 7) resection margins of 10 mm or greater. Unilobar or bilobar disease with multiple lesions is not a significant prognostic factor.